Ford Repair: 98 expedition, mass airflow sensor, k n air filter

Question
truck starts but will not idle with out a little pressure on gas pedal, i changed the fuel pump and strainer to no avail.

Answer
doesn't sound like fuel pressure problem-sounds like a vacuum leak or bad/dirty idle air control motor-throttle bore or mass airflow sensor-check and clean those three items-if you have a k & N air filter
especially check mass airflow sensor-but the most likely culprit is idle air control motor.